At least 20 people have died in Argentina and over 80 others have been hospitalised, many on ventilators, after consuming cocaine suspected of being adulterated, local government officials said.
The cases are clustered around several towns in Buenos Aires province, the country's most populous and home to many suburbs of the national capital, where community anger was rising as police carried out investigations and raids.
"We want justice and that they clean house here because here there was no drug den or anything, just my cousin who used it," said a resident of the impoverished Puerta 8 neighborhood of Buenos Aires, who said she lost one relative and had another in the hospital.
Officials believe that some of the victims suffered from opioid intoxication, a statement from the province's health ministry said.
"Currently there are 49 people hospitalised, of whom 21 are receiving mechanical respiratory assistance," a provincial government source said.
Beatriz Mercau was waiting on a bench at a hospital in Hurlingham for news about her son Ariel, who she said had been admitted for cocaine poisoning.
"He entered with cardiac arrest, without breathing and his brain was left without oxygen," she said. "They told me yesterday that his situation was serious, that we had to wait to see how things evolved."
Marcelo Lapargo, attorney general in San Martin who is in charge of the investigation, said in a television interview with C5N that they were waiting for the results of the toxicological studies to determine the contents of the drug.
He said 10 people had been arrested, of whom six were detained.
"It could be a conflict between rival gangs. I don't tend to believe that it was something unintentional... I'm extremely concerned for people who still have this in their pockets and may still consume it," Lapargo said.
Investigators said that in raids they had seized thousands of doses of cocaine, pistols, ammunition, cash and mobile phones.
Some local media outlets reported that the cocaine had been 'cut' with a toxic substance, possibly by a drug gang looking to reduce costs amid a turf war with rival groups. One relative claimed the drugs had been laced with rat poison.
Investigators said they still do not know what the cocaine was contaminated with. Reuters could not independently verify the claim that the substance was rat poison.
On Wednesday Argentina time, the Buenos Aires health ministry declared an epidemiological alert and reinforced the distribution of medicines for the treatment of patients in hospitals.
"Drugs kill, cocaine kills," said a person who gave his name as Leonardo and said his brother was in a serious condition in hospital. "I don't know what happened, whether it was done on purpose to kill."
"What can I tell you, this situation is serious because many have died."